Borehole orientation tool

ABSTRACT

The particular embodiment described herein as illustrative of one form of the invention utilizes a device for detecting the angular position and directional orientation of a housing within a wellbore and for generating a signal indicative of such information for transmission to the earth&#39;&#39;s surface.

v United States atent [151 3,693,142

Jones 51 Sept. 19, 1972 [54] BOREHOLE ORIENTATION TOOL 3,137,077 6/ 1964Rosenthal ..33/205 Inventor: Jack w. Jones 503 N. Central 3,478,83911/1969 Zemanek, Jr ..340/18 pre y c a d Tex Lunde X 2,992,492 7/1961Roussin ..33/205 [22] Filed: Nov. 21, 1969 3,434,219 3/1969 Bowman..33/205 [211 App! 879010 Primary Examiner-Richard A. Farley AssistantExaminer-H. A. Birmiel [52] US. Cl ..340/18 R, 33/205, 175/45,Attorney-George L. Church, Donald R. Johnson,

' 340/18 P, 340/18 CM Wilmer E. Corquodale, Jr. and John E. Holder [51]Int. Cl. ..G0lv 1/40 [58] Field ofSearch.340/l8 CM, 18 P, 18 R; 175/45;[57] ABSTRACT 33/20 S The particular embodiment described herein asillustrative of one form of the invention utilizes a device [56]Reierences (Med for detecting the angular position and directionalUNITED STATES NT orientation of a housing within a wellbore and foreneratin a si al indicative of such information for 2,317,632 4/1943Miller ..33/205.5 E fransmissigon can surfam 3,400,464 9/1968 Karo]..33/205 2,746,162 5/1956 Picard ..33/205 8 Claims, 4 Drawing FiguresPULSE GENERATOR l3 I04 rose IOB PENDULUM PENDULUM l FLIP-FLOP I 107 GATE14v-w PENDULUM 0PENDULUM 2 2 FLIPFLOP DATA DATA COUNTER a PROCESSINGSTORAGE UNIT PROCESSED DATA RECORDING PATENTEDSEP 19 I912 3.693; 142

SHEET 1 0F 2 PULSE I GENERATOR I3 :04 I06 L I08 PENDULUM d PENDULUM I3 Ig lFLlP-FLOP g J [09 1o? GATE |6v /l2 4% L PENDULUM PENDULUM 2 2FLIP-FLOP GATE 2 GYRO mm x FLIP-FLOP GATE 3 23% DATA DATA COUNTER aPROCESSING sToRAGE 24/ UNIT PROCESSED DATA FIG. 4

RECORDING INVENTOR JACK W. JONES AT TORNEY Pmmmssmmzz 3.693142 SHEET 2BF 2 FIG. 2 F K3. 3

INVENTOR JACK W. JONES ATTORNE Y 1 BOREHOLE ORIENTATION TOOL BACKGROUNDOF THE INVENTION This invention relates to a position sensing device andmore particularly to an apparatus for sensing the position of an objectand providing an electrical signal indicative of the attitude of suchobject. During the drilling of boreholes in the earth, it is oftendesirable to determine the attitude of the hole, not only at the bottomof the hole, but throughout its traverse of earth formations. It is forthis reason that various apparatus and methods have been devised formaking such determinations of borehole attitude. Normally such systemsconsist of apparatus for measuring the angular disposition of the holewith respect to some reference such as a horizontal reference plane, andin addition, means for determining the direction of the hole withrespect to a reference such as Magnetic North. A typical apparatus formaking such determinations of a borehole position consists of aninstrument unit, including a compass or a gyro, together with an angularunit having a plumbob arrangement, and a photographic device of somesort for making a photographic recording of the instruments in thewellbore. In the past, these instruments have been run on wirelines orgodeviled into the drill pipe where they are subsequently retrieved asin the latter case, by removing the drill pipe from the borehole. Uponretrieval of the instrument to the surface, the photographic equipmentis removed and the exposed film record of the instrument recordings isthen removed to a suitable location for developing the film. Thereafter,if calculations are to be made regarding the orientation of theborehole, such information derived from the film can then be utilized incomputation equipment for making such determinations. In any event, theprocedure outlined above is time consuming, and if decisions forcontinuing drilling or for making changes in the orientation of the wellbore are required, then such decisions must be held in abeyance untilthe film is developed and computations can be made from the indicatedparameters of the well borehole.

It is therefore an object of the prevent invention to provide a new andimproved apparatus for determining the positional orientation of anobject.

SUMMARY OF THE INVENTION With this and other objects in view, thepresent invention contemplates an instrument for use in a boreholewithin the earth for detecting and sending signals to the surfaceindicative of the orientation of the apparatus within the borehole.

The device may be comprised of separate units for detecting differentparameters of orientation. The units are comprised of a scanning deviceand means actuable in response to the scanning device for sending afirst signal to the surface indicative of the reference position on theapparatus relative to the apparatus housing. A second signal is sent tothe surface and is indicative of the position of a member within theapparatus housing in turn which is determinative of a positionalparameter of the housing within the borehole. The scanning means is timepulsed so that it may be determined, by counting such pulses between thefirst and second signals, what the angular difference is between thefirst and second signals. This angular difference may be translated intoterms of degree of direction or degrees of angular deviation.

A complete understanding of this invention may be had by reference tothe following detailed description, when considered in conjunction withthe accompanying drawings illustrating embodiments thereof.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a schematic view of awellbore tool including instruments for measuring angular and azimuthalparameters of the tool position;

FIG. 2 is a partial cross sectional view of a wellbore instrument formeasuring the angular orientation of the instrument within the wellbore;

FIG. 3 is a partial cross sectional view of a wellbore instrument formeasuring the directional orientation of the instrument within thewellbore; and

FIG. 4 is a schematic drawing of a system for transmitting wellboreinstrument data to the surface.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus described hereinis provided in a borehole tool for detecting positional parameters of aninstrument within a borehole, and transmitting such data to the surfacewhere it is processed and recorded in a form permitting a directread-out of borehole orientation data. The apparatus forming thisinvention includes the downhole units for detecting such positionalorientation and for providing a signal to the surface indicative of suchinformation.

FIG. 1 shows a schematic of such a wellbore tool which includes an angledetecting section 12 having first and second angle detecting units 13and 14 mounted therein to measure the angular disposition of planes insection 12 which are to one another. A synchronous motor 16 ispositioned between the units to provide a source of power for drivingscanning systems within the units to thereby monitor parameters of thedetecting units which are indicative of their angular disposition. Themotor 16 has output shafts extending upwardly and downwardly therefromto drive the respective scanning systems for the first and second units13 and 14. A directional section 17 is positioned below the angledetecting section and includes mechanisms for measuring the directionalorientation of the housing relative to the earths surface. Thedirectional section 17 incorporates a gyroscope [8, a gyro motor 19, andan encoder 21 for providing a reference signal to the detecting unit. Alower section 22 houses a gyro torque motor 23 and a torque motorcircuit 24 for controlling precessing of the gyro. An upper electronicsection 26, of the tool houses an electronic scanner circuit and datacounter and storage units.

An angle detecting unit 13, 14 for generating a signal indicative of theangular position of the instrument within the borehole is shown indetail in FIG. 2 of the Drawings. The angle unit includes a partiallyenclosed housing 27, having the synchronous motor 16 mounted at itsupper end. The motor has an output shaft driven at 3,600 rpm. Betweenthe synchronous motor and housing is mounted a transmission or gearreduction section 29 which has two stages of pinion gears connected withthe output shaft 28 of the synchronous motor for reducing the outputrevolution thereof. The output of the gear reduction section is fedthrough a shaft 31 which extends longitudinally from the upper to thelower end of the instrument housing. At the lower end of the outputshaft, a worm gear 32 is rotated therewith for driving a spiroid gear33, which in turn drives a scanning system within the instrument. Thetotal gear reduction between the output of the synchronous motor and therotation of the spiroid gear within the instrument housing is from 3,600rpm of the motor to rpm of the spiroid gear 33.

The angle detector and scanning system are located within the housingand include a horizontal shaft 36 extending transversely across thehousing midway between its ends. A scanner assembly is rotatably mountedabout the left side of the shaft as viewed in FIG. 2, and is providedwith bearings 37, 38 for rotatably supporting the assembly about theshaft. The scanner assembly is comprised of a large diameter verticaldisc 39 upon one side of which is mounted the circular spiroid gearsection 33. The spiroid gear is arranged to mesh with the worm gear 32on the shaft 31 extending vertically through the housing. A sleeve 41extends outwardly from the vertical disc 39, and is positioned about thehorizontal shaft 36. An insulating cylinder 42 is positioned about thesleeve. Grooved commutator rings 43 are positioned about the insulator.The grooved commutators are electrically insulated from one another toprovide separate electrical flow paths between the stationary portion ofthe instrument housing and the rotating scanner section. An insulatingpost 44 is positioned above the commutators and is connected to the sidewall of the housing. Brushes 66 extend downwardly from the post intocontact with the commutators. The upper ends of the brushes areconnected to terminal posts 47 to provide a means for electricallyconnecting the brushes with conductor wires (not shown) within theinstrument hous- Referring again to the vertical disc 39 of the scannersection, a lamp 48 and lamp housing 49 are shown extending outwardlyfrom the outer rim of disc 39 toward the center of the housing. A firstlongitudinal slit 51 is formed in the outer wall of the lamp housing andis perpendicular to the shaft 36. A second longitudinal slit 52 isformed along the bottom portion of the lamp housing 49 and is parallelwith the shaft 36. A detector photocell 53 and housing 54 are mounted onthe disc 39 and extend outwardly from the discon the same side as thelamp 48 and housing 49. Wires (not shown) extend from the photocellthrough the disc and into contact with the commutator rings. Thephotocell housing has a slit or opening 56 in its upper side wall andparallel to the shaft 36 to permit light emanating from lamp 48 toproject into the housing for activating the photocell. Conductor wiresare also provided to the lamp housing from the commutator rings toprovide an electrical power source to the lamp.

A pendulum assembly is also mounted on the horizontal shaft 36 oppositethe scanner assembly. The pendulum assembly is comprised of an annularsleeve 57 positioned about the shaft and rotatably supported thereon bymeans of bearings at each end of the annular sleeve. A circular shield58 extends outwardly from the sleeve and includes an L-shaped endportion 59 extending inwardly therefrom toward the circular disc 39 ofthe scanner section. The inwardly extending portion 59 of the shieldapproaches contact with the vertically mounted disc 36, but does notcontact the disc, so that the pendulum assembly is free to moveindependently with respect to the scanner assembly. The shield and itsinwardly extending portion are arranged to pass over and about thedetector photocell 53 and housing 54. The inwardly extending portion ofthe shield passes between the bottom of the lamp housing 49 and theupper side of the photocell detector housing 54. A slit 61 is formed inthe inwardly extending portion of the sleeve in parallel relationshipwith the slit 52 formed in the lower side of the lamp housing. Aweighted pendulum member 63 is connected to the shield 58 and covers apartial segment of the shield. This weighted pendulum member maintainsthe shield in an oriented position relative to gravity, regardless ofthe position of the housing with respect to gravity, since the pendulumassembly is freely mounted for rotation upon the horizontal shaft 36.The slit 61 in the inwardly extending portion 59 of the shield ispositioned at a point thereon corresponding to a point on the peripheryof the weighted pendulum member 63 directly below the center of gravityof the weighted member when the member is at free rest relative togravity.

Also mounted within the interior of the housing is a second or referencephotocell or other such light sensitive device 64, which is positionedat the upper end of the interior portion of the instrument housingopposite a point on the path of movement of the lamp 48. A vertical slit66 is provided within the outer wall of the photocell housing 67, whichslit is arranged to be oppositely disposed and parallel to the verticalslit 5] in the lamp housing 49. Conductor wires (not shown) provide anelectrical power source for the photocell 64.

In the operation of the apparatus just described, the synchronous motor16 is continuously driving the gear reducing mechanism to rotate thespiroid gear 33 and scanner disc at a rate of 20 revolutions per minuteor l revolution every 3 seconds. This means that the lamp 48 on-thescanner disc 39 will pass in front of the reference photocell 64 on theinterior wall of the housing, once every 3 seconds. The lamp 48 iscontinuously energized. As a result, the reference photocell will beactivated to generate a signal once every 3 seconds for purposes to behereinafter described.

As the scanner disc and lamp continue to rotate during each revolution,a second signal is generated when the lamp 48 passes the slit 61 in theinwardly extending portion of the pendulum shield. The slit 61 permitslight from the lamp to impinge upon the detector photocell 53 which ispositioned on the scanner disc 39 next to the lamp 48. The shieldnormally prevents the lamp from activating the photocell 53, except whenthe lamp and photocell pass the slit 6] in the pendulum once during eachrevolution of the disc. The slit in the shield is positioned relative tothe gravitational pull of the weighted pendulum member, so that eventhough the housing is tilted at an angle with respect to the vertical,the shield will remain in a constant position determined by the force ofgravity. Therefore, the slit 61 in the shield will always remain at thebottom (relative to earth s gravity) of the pendulous shield. As thelamp 48 and photo detector cell 53, which are mounted on the scannerdisc move past the slit 61 in the pendulum shield at its lower side, thelight emanating from the lamp will pass through the slit and beprojected upon the detector photocell, which in turn generates a signalthat is picked up from the commutator rings and brushes for purposes tobe hereinafter described.

It is readily seen that as the scanning disc 39 rotates, a pulse isgenerated once every 3 seconds by the case reference photocell 64, andthat a second pulse is generated at some time lapse after the first casereference photocell pulse is generated, depending upon the position ofthe slit 61 in the pendulum shield relative to the case referencephotocell. If, for example, the instrument housing were lying in ahorizontal position with respect to the surface of the earth, thescanner, if operating in a clockwise direction, (as viewed from theright side as shown in FIG. 2) would generate a first signal when thelamp 48 passes the slit 66 in the case reference photocell housing.Ninety rotational degrees thereafter, the scanner would generate asecond signal when the lamp 48 passes the slit 61 in the pendulum shieldto activate photocell 53. If the time rate of rotation of the scanningdisc 39 is known, then the actual number of degrees transgressed by thescanning mechanism between such first and second signals may becalculated.

In order to provide completely accurate information as to the angularposition of the instrument housing with respect to a vertical referenceplane, it is desirable to utilize a second angle detecting unit 14,which is mounted so that the scanning disc and pendulum shield of thesecond instrument are in a vertical plane perpendicular to that of theplane of the shield and disc in the first instance. As will be describedhereinafter, the data outputs of each of the pendulum instrumentsections is fed to a data processing unit where a vector summation ofthe outputs provides a true calculation of the angular disposition ofthe instrument housing.

Referring now to FIG. 3 of the drawings, details of the directional unit17 (FIG. 1) are shown. Directional unit 17 provides information relativeto the directional or azimuthal orientation of the instrument housing.The unit shown in FIG. 3 is very similar to that of FIG. 2 in that ascanning section is rotated relative to a shield, which instead of beingoriented by a pendulum, is driven by the rotation of the vertical shaft71 of the directional gyroscope 18. The vertical or output shaft 71 ofthe gyroscope is shown connected to a vertical sleeve 73, which ispress-fitted onto the output shaft of the gyro. The sleeve has anoutwardly extending shield portion 74 which in turn has an upwardlyextending circular shield wall 76. The gyro instrument housing 77 hassynchronous motor 19 and gear reduction section 79 mounted on its upperside, with the output shaft 81 of the gear section extending through thetop of the instrument housing 77 and downwardly into the instrument.Bearings are provided in the top of the instrument housing to rotatablysupport the motor driven output shaft. A scanning section is mounted onthe motor driven output shaft for rotation within the instrumenthousing. The scanner section is comprised of a vertical sleeve 82attached to the lower end of the shaft. The sleeve has an insulatedcylinder 83 about its outer walls upon which are mounted commutatorrings 84 which are electrically insulated from one another. At the lowerend of the scanner sleeve, a horizontally disposed circular disc orplate 86 is shown extending outwardly therefrom. A scanning lamp 87 isattached to the lower side of the circular disc near its outer rim andextends downwardly therefrom. A detector photocell 88 is also attachedto the under side of the disc and is mounted within a detector photocellhousing 89. A housing 91 is also disposed about the lamp, and isprovided with a first horizontal slit 92 on the bottom side of thehousing, and a second vertical slit 93 on the inner wall of the lamphousing. The upwardly extending vertical wall 76 of the shield ispositioned between the scanning lamp 87 and detector photocell 88mounted on the scanning disc. A slit 95 is formed in the vertical wallof the shield. A case reference photocell 94 is mounted within a housing96 upon the inner wall of the instrument housing in a spaced rela tionwith the outer rim of the scannerdisc and the lamp 87. Clearance isprovided between the reference photocell housing 96 and the lamp housing91. A slit 97 is provided in the top side of the case referencephotocell housing to permit light emanating from the lamp housing toimpinge upon the photocell 94.

An insulating block 98 is shown extending downwardly from the upper endof the instrument housing. The block holds horizontally disposed brushes99 therein for contacting commutator rings 100 on the scanning sleeve.Terminal members 101 are connected to the brushes to provide electricalcontact with conducting wires (not shown) for supplying electrical powerto the lamp and for transmitting a signal from the detector photocell toelectrical circuitry within the instrument. Likewise, suitable conductorwires are connected with the case reference photocell to provide a meansfor transmitting a signal therefrom to such electrical circuitry withinthe instrument housing.

A shaft 102 also extends upwardly from the motor section 19 of theinstrument for driving an encoder 21. The output shaft from the motor isrotated at 3,600 rpm, or 60 revolutions per second. The encoder isarranged to be run from the output shaft of the motor and to multiplysuch rotation of the output shaft as to provide l2,000 pulses per secondfrom the encoder.

The gear reduction section 79 is placed between the output shaft of themotor and the scanning device in the instrument housing so that thescanner is operated at 20 rpm, or 1 revolution every 3 seconds.Therefore, when the scanning mechanism has made one revolution withinthe instrument housing, in 3 seconds, the encoder or pulse generator hasproduced 36,000 pulses. As will be described later, this relationshipbetween the encoder pulses and the scanner rotation readily permits adetermination of degrees of scanner rotation between signals from thefirst and second photocells to an accuracy of 001. It is also seen thatsynchronization between the scanning mechanism in the instrument and thepulses generated by the encoder prevents any variation in the powersupply from effecting the readout.

Any variation in the operation of the motor from its intended 3,600 rpmwill provide a proportional relationship between the rotational speed ofthe scanner and the output pulses from the pulse generator. The motordriving the angle detecting units is driven synchronously with motor 78and encoder pulses from encoder 103 are also provided to circuitry forreading the angle units.

Referring next to FIG. 4 of the Drawings, a schematic representation ofan electrical system for utilizing the information derived from theangle and azimuth units is shown. The pendulum 1 and 2 angle detectingunits 13, 14 respectively and the gyro instrument section are shownhaving output lines leading to respective flip flop circuits. Forexample, the first output 104 of the pendulum 1 unit represents thescanning signal derived from the case reference photocell. This casereference signal places a pendulum 1 flip flop circuit 106 in conditionto conduct and thus provide an output signal 107 through a conductor toan associated AND gate circuit 108, which is labeled Gate 1. A secondsignal output 109 from the pendulum 1 scanning section represents asignal derived from the detector photocell 53. The circuit is arrangedso that this detector signal causes the pendulum I flip flop 106 tocease operation which in turn stops the flip flop output signal 107 toGate 1.

During operation of the flip flop by the scanning signals, pulses fromthe pulse generator or encoder 21 are fed at the rate of 12,000 pulsesper second to the Gates 1, 2, and 3 of the pendulum 1, 2, and the gyrorespectively. When the respective flip flops are operating, pulses fromthe pulse generator will be countered or passed by the gate to a datacounter and storage unit 111. when the flip flop ceases to operate, thegate discontinues passage of the pulses from the pulse generator to thedata counter. Therefore, the duration of the signals from the flip flopswill determine the time that such pulses are passed through the gatecircuits to the data counter.

Referring again to the pendulum 1 instrument, when the scanning lamppasses the case reference photocell, the pendulum 1 flip flop isactivated, which in turn sends the output signal 107 to Gate 1. Thisoutput 107 opens Gate 1 to permit the passage of pulses generated by thepulse generator to the data counter and storage unit. Such a signal fromthe flip flop will continue until the lamp 48 on the scanner passes theslit 61 in the pendulum shield to generate a signal output 109 from thedetector photocell 53. The output 109 will cause operation of flip flop106 to cease and thereby close Gate 108. The gate will thus ceasepassing the pulses generated by the pulse generator to the data counter.For example, if the scanner lamp 48 takes 1 k seconds to move from thereference photocell to the detector photocell, the flip flop will beoutputting a signal for 1 k seconds. The gate therefore will be open forl k seconds. During this time span, 18, -0 pulses from the pulsegenerator will be passed by the pendulum 1 gate to the data counter.Since the scanner rotates at a rate of l revolution every 3 seconds, thescanner will have moved in the l k seconds over an arc of 180.00, thusthe detector photocell is located 180 from the reference photocell. Thisindicates that the detector housing is in a vertical position, and thattherefore the wellbore is in a vertically oriented position, since theslit 66 in the reference photocell, which is at the top of the housingis, in fact, 180 away from the slit 61 in the pendulum shield which islocated at the bottom center of the pendulum.

Operation of the gyro unit in the instrument is similar to thatdescribed above with respect to the pendulum units. The referencephotocell on the azimuth unit is photocell 08. The slit 95 which permitslight from lamp 87 to impinge upon the photocell 88 is oriented withrespect to the tool housing and one of the pendulum units which in turnis oriented with respect to Magnetic North at the earth's surface. Whilethe gyro unit housing turns in the wellbore, the gyro and slit 95 remainoriented with respect to Magnetic North. Thus, when the scanner lamp 87passes the slit 95, the associated flip flop begins to conduct until thescanner lamp passes slit 97 to operate photocell 94. The pulses passedby gate 3 during this time span are likewise indicative of azimuthaldegrees of difference between Magnetic North and the reference photocell94 on the gyro unit housing. Since the gyro unit is referenced to thependulum units and Magnetic North, the readings from these units may becombined to give a true angular and azimuthal orientation of the toolhousing. First the outputs of the angle units are summed vectorially toprovide an angle of inclination of the housing. Then, if the gyro unitoutput indicates that the housing has rotated X from North, thependulums have moved the same amount, and the vector summation islikewise rotated X. The resultant computation gives the angulardisposition of the housing relative to Magnetic North or similar surfacereference.

The pulses which are supplied to the data counter from the subsurfaceunits are stored in the counter and storage unit in binary form. Afterthe information is read out of the pendulum l gate into the counter andstorage unit, a switch causes information from the pen dulum 2 gate topass into the data counter and storage unit in the same manner, andlikewise with the gyro unit. This information in turn is fed into thedata processing unit at the surface, where the information relative tothe pendulum l and pendulum 2 positions is used to calculate the angulardisposition of the pendulums by performing a vector summation of thevalues supplied by each of the units which are located to one another inthe instrument housing. The gyro information is then combined with suchangular information to provide data which will be indicative of theorientation of the tool, and therefore the borehole. This informationmay then be printed out in any wellknown manner or recorded for futureuse.

The data counter and storage unit consists of three sixteen bit, countand store units. By using counting and storage units, or clock gatedflip flops" as they are called, information may be read out from thestorage units, while new information is gathered from the scanningsystems into the counter units. Thus, the information in the storageunits is continuously up dated, and is always available for immediateread-out. The pendulum and gyro units are continuously scanned at a onesecond scan rate, and the information stored in individual storageracks. These storage racks are scanned electronically by using a 16 bitring counter driven by an oscillator or line frequency. A second threebit ring counter is driven from the 16 bit ring, and is used as agateing programmer to select the storage register to be read out. The 48bits of information from the three storage registers is read out instraight serial binary form, in one second intervals, and sent to thesurface on a single conductor line. The power to the instrument is fedover the same conductor and may be either AC or DC voltage.

Alternatively, a multiple conductor cable may be used to pass signalsfrom the Gates 1, 2, and 3 directly to the surface where they may bestored and processed in much the same manner as described above.Although described with respect to surface recording, it is readily seenthat the apparatus described herein would be compatible for use withdownhole recording equipment.

Therefore, while particular embodiments of the present invention havebeen shown and described, it is apparent that changes and modificationsmay be made without departing from this invention in its broaderaspects, and the aim in the above description is to cover all suchchanges and modifications as fall within the true spirit and scope ofthis invention.

What is claimed is:

1. Ina position sensing and indicating apparatus for use in a borehole:a housing arranged to be suspended in a borehole on a cable; a firstangle detecting unit; a second angle detecting unit; counter means,means for supplying pulses to said counter, means for generating signalsindicative of the angular disposition of said first and second units;means responsive to such generated signals for operating said counter;means for storing countered pulses corresponding to such generatedsignals; and surface means for providing an indication of such angulardisposition in response to such stored counted pulses.

2. The apparatus of claim 1 wherein said first and second angledetecting units are mounted in said housing in planes 90 to one another.

3. The apparatus of claim 1 wherein said signal generating meansincludes means for scanning said angle detecting units and means forgenerating a first reference signal indicative of a reference mark onthe housing and a second signal corresponding to the angular dispositionof the angle detecting units relative to said reference mark, said firstreference signal and said second signal being used to operate saidcounter.

4. In a position sensing instrument: a housing; angle detecting means insaid housing for measuring a parameter of the angular disposition of thehousing; azimuth position sensing means in said housing for measuring aparameter of the azimuthal disposition of the housing; means forgenerating signals indicative of such angular and azimuthal parameters;pulse generating means; pulse counting means; means responsive to saidsignal generating means for operating said pulse counting means; andsurface means for providing an indication of such counted pulses.

5. The apparatus of claim 4 wherein said angle detecting means includesmeans in said housing for indicating a reference position; and means insaid housing for indicating the position of a member independent of theposition of said housing.

6. The apparatus of claim 5 wherein said signal generating meansincludes means initiating a first signal indicative of the referenceposition on said housing for operating said pulse counting means; andmeans initiating a second signal indicative of the relative position ofsaid member to said reference position on said housing for stopping theoperation of said counting means.

7. A method for determining the disposition of a borehole within theearth relative to the earth s surface, comprising the steps of: loweringa housing into the wellbore; detecting and measuring a parameter of thean ular dis osition of a first plane of said housing; de tec mg anmeasuring a parameter of the angular disposition of a second plane ofsaid housing to said first plane; detecting and measuring a parameter ofthe azimuthal disposition of said housing; generating electrical signalswithin said housing which are representative of the measured parameters;supplying timed pulses to a counter; operating the counter in responseto such generated electrical signals; transmitting data corresponding tosuch counted pulses to the earths surface; and calculating from thetransmitted data, the position of such housing in the borehole relativeto the earth 5 surface.

8. The method of claim 7 wherein said calculation involves making avector summation of the angular parameters measured in planes 90 to oneanother, and orienting such vector summation with respect to themeasured azimuthal parameters.

1. In a position sensing and indicating apparatus for use in a borehole:a housing arranged to be suspended in a borehole on a cable; a firstangle detecting unit; a second angle detecting unit; counter means,means for supplying pulses to said counter, means for generating signalsindicative of the angular disposition of said first and second units;means responsive to such generated signals for operating said counter;means for storing countered pulses corresponding to such generatedsignals; and surface means for providing an indication of such angulardisposition in response to such stored counted pulses.
 2. The apparatusof claim 1 wherein said first and second angle detecting units aremounted in said housing in planes 90* to one another.
 3. The apparatusof claim 1 wherein said signal generating means includes means forscanning said angle detecting units and means for generating a firstreference signal indicative of a reference mark on the housing and asecond signal corresponding to the angular disposition of the angledetecting units relative to said reference mark, said first referencesignal and said second signal being used to operate said counter.
 4. Ina position sensing instrument: a housing; angle detecting means in saidhousing for measuring a parameter of the angular disposition of thehousing; azimuth position sensing means in said housing for measuring aparameter of the azimuthal disposition of the housing; means forgenerating signals indicative of such angular and azimuthal parameters;pulse generating means; pulse counting means; means responsive to saidsignal generating means for operating said pulse counting means; andsurface means for providing an indication of such counted pulses.
 5. Theapparatus of claim 4 wherein said angle detecting means includes meansin said housing for indicating a reference position; and means in saidhousing for indicating the position of a member independent of theposition of said housing.
 6. The apparatus of claim 5 wherein saidsignal generating means includes means initiating a first signalindicative of the reference position on said housing for operating saidpulse counting means; and means initiating a second signal indicative ofthe relative position of said member to said reference position on saidhousing for stopping the operation of said counting means.
 7. A methodfor determining the disposition of a borehole within the earth relativeto the earth''s surface, comprising the steps of: lowering a housinginto the wellbore; detecting and measuring a parameter of the angulardisposition of a first plane of said housing; detecting and measuring aparameter of the angular disposition of a second plane of said housing90* to said first plane; detecting and measuring a parameter of theazimuthal disposition of said housing; generating electrical signalswithin said housing which are representative of the measured parameters;supplying timed pulses to a counter; operating the counter in responseto such generated electrical signals; transmitting data corresponding tosuch counted pulses to the earth''s surface; and calculating from thetransmitted data, the position of such housing in the borehole relativeto the earth''s surface.
 8. The method of claim 7 wherein saidcalculation involves making a vector summation of the angular parametersmeasured in planes 90* to one another, and orienting such vectorsummation with respect to the measured azimuthal parameters.